Adaptable sound quality device

ABSTRACT

Devices for monitoring a sound pressure level of sound generated by a speaker. For example, the device may sample voltages at various points along a path of an audio signal, determine a current associated with the audio signal, and receive or infer an efficiency of the speaker. The device may then determine the sound pressure level based on the voltage, the current, and the efficiency to more accurately monitor the sound pressure level exposure of a user.

BACKGROUND

Exposure to audio signals at greater and greater amplitudes through theuse of headphones and media devices, such as cell phones and MP3players, has been increasing at an alarming rate. Exposure to audiosignals at high decibel levels has been determined to be one of theprimary causes of temporary and permanent hearing impairment, sometimescalled noise-induced hearing loss. However, hearing impairment is notonly increasing in the general population, but is increasing at asignificantly faster rate among young people, especially in among thosewho utilize media devices and wear headphones (or wireless earpieces)for significant amounts of time.

The extent of hearing damage sustained through exposure to sounds hasbeen determined to be a function of both the amplitude and the durationof the audio signals, and particularly exposure to audio signals atamplitudes that exceed a safe acoustic threshold. Permanent hearingdamage is a cumulative effect of exceeding the minimum thresholds orsafe pressure levels for extended periods. Various administrative bodies(such as the Occupational Safety and Health Administration (OSHA)) andhealth awareness agencies (such as the National Institute forOccupational Safety and Health (NIOSH)) have adopted guidelines for safeacoustic levels and listening durations

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical components or features.

FIG. 1 illustrates an example system including a sound quality deviceaccording to some implementations.

FIG. 2 illustrates a partial circuit diagram showing select componentsof a sound quality device of a system according to some implementations.

FIG. 3 illustrates a partial circuit diagram showing select componentsof a sound quality device of a system according to some implementations.

FIG. 4 illustrates a partial circuit diagram showing select componentsof a sound quality device according to some implementations.

FIG. 5 illustrates a partial circuit diagram showing select componentsof a sound quality device according to some implementations.

FIG. 6 illustrates a partial circuit diagram showing a select componentto modify the audio signal according to the circuit of FIG. 5.

FIG. 7 is an example flow diagram showing an illustrative processaccording to some implementations.

FIG. 8 is an example flow diagram showing an illustrative processaccording to some implementations.

FIG. 9 is an example flow diagram showing an illustrative processaccording to some implementations.

FIG. 10 is an example flow diagram showing an illustrative processaccording to some implementations.

FIG. 11 is an example flow diagram showing an illustrative processaccording to some implementations.

FIG. 12 illustrates an example architecture of an audio device of FIGS.1-5 according to some implementations.

FIG. 13 illustrates an example architecture of a sound quality device ofFIGS. 1-5 according to some implementations.

DETAILED DESCRIPTION

This disclosure includes techniques and implementations to improvequality of sound output by speakers, in-ear monitors, or headsets. Inparticular, this disclosure describes ways to monitor sound pressurelevel associated with the audio output by a speaker and to alert whenhearing damage may be occurring. For example, studies indicate thatsustained exposure to noise levels in excess of 85 weighed decibels(dBA) and/or short and loud noises above a peak threshold (e.g.,approximately 140 dBA) can permanently damage hearing. Further, OSHA hasdefined noise level exposure limits based on sound pressure over time.For example, OSHA has defined listening to sound or music over 90 dBAfor more than eight hours within a 24 period to cause permeant damage.

Described herein are implementations of a sound quality device that maybe coupled between an audio source and an output device (e.g., aspeaker) that may monitor the sound pressure level of the soundgenerated by the output device in real time and notify the user if thesound pressure level presents a danger to the user's hearing. In someparticular implementations, the sound quality device may also reduce orlower the sound pressure level.

In general, sound pressure level is a result of the current of the audiosignal, the voltage of the audio signal, and the efficiency of thespeaker that outputs the audio. However, in many cases, the audio sourceis associated with a different device or product than the speaker (e.g.,a smart phone or audio player versus a headset or earbud system). Inthese cases, the audio source may be aware of the voltage level but notthe current or efficiency, while the output device may be aware of theefficiency but not the voltage or current. Thus, in these cases,calculating and/or monitoring the sound pressure level may be difficult.

In one example, the sound quality device may be configured to measurethe voltage and current associated with the audio signal as the singlepasses through the sound quality device. The sound quality device may insome cases calculate the sound pressure level using the sampled voltage,the calculated or measured current, and an estimated efficiency. In thisexample, by measuring both the current and voltage the estimated soundpressure level may be more accurate than when merely the voltage isknown. Likewise, the estimated sound pressure level may be more accuratethan when merely the efficiency is known.

In one particular implementation, the sound quality device may include apath or circuit that includes a known resistive value (e.g., a resistoror series of resistors placed in the path). The sound quality device maysample the voltage of the audio signal at a first point on the pathbefore the known resistive value and a second point on the path afterthe known resistive value. The sound quality device may then calculateboth the current and the current using the two sampled values. Forexample, the voltage is the voltage at the second point and the currentmay be equal to the voltage at the second point minus the voltage at thefirst point divided by the known resistive value.

In some cases, the sound quality device may estimate the impedance ofthe speaker or earbud by causing the audio source to emit a known orexpected tone or audio signal which may be used to calculate thevoltages at the first and second points on the path. Using the twovoltages, and the known resistive value between the first and secondpoints, the current value can be calculated. Further, by dividing thevoltage and the second point by the current, the impedance of thespeaker or earbud can be calculated.

Additionally, in some examples, each of the measured voltages mayinclude a series of measured voltages. For instance, the audio sourcemay generate a signal representative of a sine wave. The sound qualitydevice may then take a series of voltage measurements at the first pointand a series of voltage measures at the second point. The sound qualitydevice may then take the root mean square of the voltages measured atthe first point to determine the first voltage and the root mean squareof the voltage measured at the second point to determine the secondvoltage. The first and second voltages may then be utilized to calculatethe current, impedance, and/or sound pressure level.

In some examples, the efficiency may be estimated to be a static valuebased at least in part on an average efficiency or a thresholdefficiency. For instance, the efficiency by be set to ten percent,twenty percent, or even thirty percent. In other examples, theefficiency of the speaker may also be known or obtained by the soundquality device. For example, the audio source may be a smart phone orother user interactive device. The audio source may store an applicationthat may be utilized by a user of the audio source to select or enterinformation associated with the speaker being used. In one instance, theuser may enter a make and model of the speaker or headset and theapplication operation on the audio source may look up the efficiency ina look up table stored on the audio source or via one or more networks(such as the Internet®).

In some examples, the sound quality device may be configured to notifythe user to any risk of permanent hearing damage caused by over exposureto sound based OSHA or other guidelines. For example, the sound qualitydevice may include multiple paths each having a different resistivevalue associated thereto. The sound quality device may be configured toswitch between the resistive paths to cause a clicking or noticeablechange in the sound output by the speaker to alert the user to thepotential for hearing damage. In other examples, the sound qualitydevice may cause the audio source to generate an alert for the user. Forinstance, the sound quality device may cause the audio source tovibrate, glows, activate a light, turn on, turn off, present anotification on the display, etc.

In other cases, the sound quality device may be configured to increaseor decrease the resistive value that the audio signal passes throughbased on the sound pressure level experienced by the user. For instance,the sound quality device may switch to a path having a higher overallresistance to reduce the voltage and/or current associated with theaudio signal output as sound, thereby reducing the sound pressure levelwithout requiring a change in the volume level at the audio source.

In one particular example, the sound quality device may act as a screamprotection device. For instance, when switching audio signals (e.g.,when switching from audio generated by an streaming application hostedon the audio source to audio from a music player application on theaudio source) the volume level associated with the audio signal maydiffer. In these cases, the sound quality device may switch to a highresistive path for a predetermined amount of time upon the activation ofthe device, receiving a new or different audio signal, or at any timethe sound pressure level exceeds a threshold. In this manner, when theaudio source is first turned on the user may be protected from anexceptionally loud noise being output at the speaker due to the volumebeing left in an elevated state when the audio device was deactivated.Similarly, the user hearing may be protected if the volume on the audiosignal is suddenly increased, for instance as is common, during anexplosion on an audio track associated with a movie or television show.

FIG. 1 illustrates an example system 100 including a sound qualitydevice 102 according to some implementations. In the illustratedexample, the sound quality device 102 is shown as a separate device thatmay couple between an audio source 104 and an output device 106, such asthe headset 108 (ear buds) or the speaker 110. For example, the outputdevice 106 may couple to the sound quality device 102 via a TRS jack orother type of audio input 112 and the sound quality device 102 may alsocouple to the amplifier 104 via a TRS jack or other type of audio input114.

In some cases, the sound quality device 102 may include an audio pathincluding a known restive value. The sound quality 102 device may beconfigured to sample the voltage of the audio signal 116 at a firstpoint on the path before the known resistive value and a second point onthe path after the known resistive value. In some cases, sound qualitydevice may sample a series of voltages at the first point and a seriesof voltages at the second point. The sound quality device may determinethe voltage at the first point based at least in part on a root meansquare of the series of voltages sampled at the first point and thevoltage at the second point based at least in part on the root meansquare of the series of voltage sampled at the second point.

The sound quality device 102 may calculate both the voltage and thecurrent using the two sampled values. For example, the voltage may bethe voltage at the second point (e.g., the voltage received by theoutput device 106) and the measured current may be equal to the voltageat the second point minus the voltage at the first point divided by theknown resistive value.

In some examples, an efficiency 118 may be a static value based at leastin part on an average efficiency or a threshold efficiency. Forinstance, the efficiency 118 by be set to ninety five percent, ninetyeight percent, or even ninety nine percent of the output device 106. Inother examples, such as the illustrated example, the efficiency 118 ofthe output device 106 may also be known or obtained by the sound qualitydevice 102. For example, the sound quality device 102 may be incommunication with the audio source 104 via a network 120 (e.g., a shortrange wireless communication network, such as Bluetooth®). The audiosource 104 may then store a sound quality application that may beutilized by a user of the audio source 104 to select or enterinformation associated with the output device 106 being used. In oneinstance, the user may enter a make and model of the speaker or headsetand the sound quality application operation on the audio source 104 maylook up the efficiency 118 in a look up table stored on the audio source104 or via one or more networks (such as the Internet®) and provide theefficiency 118 to the sound quality device 102.

In some examples, the sound quality device 102 may be configured toalert 122 the user to any risk of permanent hearing damage caused byover exposure to sound based OSHA or other guidelines. In oneimplementation, the sound quality device 102 may include multiple pathseach having a different resistive value associated thereto. The soundquality device 102 may be configured to switch between the resistivepaths to cause a clicking or noticeable change in the sound output bythe speaker to alert 122 the user to the potential for hearing damage.In other examples, the sound quality device 102 may provide anindication of the alert 122 to the audio source 104 to cause the audiosource 104 to notify the user. For instance, the audio source 104 mayvibrate, glows, activate a light, turn on, turn off, present anotification on the display, etc. in response to receiving theindication of the alert 122 form the sound quality device 102.

FIG. 2 illustrates a partial circuit diagram showing select componentsof a sound quality device 202 of a system 200 according to someimplementations. In the illustrated example, the sound quality device202 is coupled between an audio source 204 and the output device 206 andincludes, in part, a circuit 208 between the audio source 204 and theoutput device 206 to facilitate the output of an audio signal generatedby the audio source 204 as sound by the output device 206.

The circuit 208 includes at least one resistive value 210. The restivevalue 210 may be the resistive value of the routing wire between points216 and 220 and/or an additional resistive element introduced into thepath 214 between the points 216 and 220. The circuit 208 may alsoinclude a first analog to digital converter 212 coupled on a path 214 ofthe audio signal from the audio source 204 to the output device 206 at apoint 216. The circuit also includes a second analog-to-digitalconverter 218 coupled to the path 214 at a point 220. Both the firstanalog-to-digital converter 212 and the second analog-to-digitalconverter 218 may be further coupled to one or more processors 222 fordetermining a voltage at the output device 206 and a current at outputdevice 206.

In one example, the processors 222 may receive a first sample of thevoltage of the audio signal at the point 216 via the analog-to-digitalconverter 212 and a second sample of the voltage of the audio signal atthe point 220 via the analog-to-digital converter 218. The processor 222may then calculate the current of the audio signal at the output device206 by subtracting the voltage sampled at the first point from thevoltage sampled at the second point and dividing the result by theresistive value 210.

Once the current is measured or calculated, the processors 222 maycalculate the sound pressure level by multiplying the voltage sampled atthe point 220 by the current calculated above and a value indicative ofthe efficiency of the output device 206. In some cases, the processor222 may obtain or request the efficiency from the computer readablemedia 224.

FIG. 3 illustrates a partial circuit diagram showing select componentsof a sound quality device 302 of a system 300 according to someimplementations. In the illustrated example, the sound quality device302 is coupled between an audio source 304 and the output device 306 andincludes, in part, a circuit 308 between the audio source 304 and theoutput device 306 to facilitate the output of an audio signal generatedby the audio source 304 as sound by the output device 306.

The circuit 308 includes at least one resistive value 310 having a knownresistive value 310. The restive value 310 may be the resistive value ofthe routing wire between points 316 and 320 and/or an additionalresistive element introduced into the path 314 between the points 316and 320. The circuit 308 may also include a first analog to digitalconverter 312 coupled on a path 314 of the audio signal from the audiosource 304 to the output device 306 at a point 316. The circuit alsoincludes a second analog-to-digital converter 318 coupled to the path314 at a point 320. Both the first analog-to-digital converter 312 andthe second analog-to-digital converter 318 may be further coupled to oneor more processors 322 for determining a sound pressure level of thesound generated by the output device 306.

In some cases, the processor 322 may be coupled one or morecommunication interfaces 324 for sending and receiving data from theaudio device 304 over one or more networks 326. In some cases, thenetwork 326 may be representative of wired technologies (e.g., wires,USB, fiber optic cable, etc.), wireless technologies (e.g., RF,cellular, satellite, Bluetooth, etc.), or other connection technologies.The network 326 may be representative of any type of communicationnetwork, including data and/or voice network, and may be implementedusing wired infrastructure (e.g., cable, CATS, fiber optic cable, etc.),a wireless infrastructure (e.g., RF, cellular, microwave, satellite,Bluetooth, etc.), and/or other connection technologies. The network 326may carry data (for example, efficiency values 328) between the soundquality device 302 and the audio source 304.

In one example, the processors 322 may receive a first sample of thevoltage of the audio signal at the point 316 via the analog-to-digitalconverter 312 and a second sample of the voltage of the audio signal atthe point 320 via the analog-to-digital converter 318. The processor 322may then calculate the current of the audio signal at the output device306 by subtracting the voltage sampled at the first point from thevoltage sampled at the second point and dividing the result by theresistive value of the resistive value 310.

Once the current is measured or calculated, the processors 322 maycalculate the sound pressure level by multiplying the voltage sampled atthe point 320 by the current calculated above and a value indicative ofthe efficiency of the output device 306. In some cases, the processor322 generates an efficiency request 330 and cause the communicationsinterfaces 324 to send the request 330 to the audio source 304. In somecases, the efficiency request 330 may include an impedance valuecalculated by the processor 322 by dividing the voltage sampled at thepoint 320 by the voltage sampled at point 316 minus the voltage sampledat the point 320. In other cases, the request 330 may include thesampled voltages and/or the calculated current, such that the audiosource 304 may calculate the efficiency 328 and/or impedance.

In one particular implementation, the request 330 may include thesampled voltages and the audio source 304 may be configured to calculatethe sound pressure level based on the sampled voltages, to monitor thesound pressure level over time, and to provide the alert 330 to the userin response to determining the output device 306 is causing damage. Forexample, the audio source 304 may vibrate, emit a noise, activate thedisplay, and cause a notification to appear on the display, or otherwisealter the user. In other cases, the sound quality device 302 maydetermine the user should be altered and, thus, the processors 322 maygenerate the alert 332 and cause the communication interfaces 324 toprovide the alert 322 to the audio source 304 for output to the user.

FIG. 4 illustrates a partial circuit diagram showing select componentsof a sound quality device 402 of a system 400 according to someimplementations. The sound quality device 400 may be configured tocouple inline between an audio source 404 and an output device 406. Inthe illustrated example, the sound quality device 302 includes, in part,a circuit 408 between the audio source 404 and the output device 406 tofacilitate the output of an audio signal generated by the audio source404 as sound by the output device 406.

The circuit 408 includes a plurality of resistive elements, generallyindicated by 410(1)-(N), along the path 414. Each of the restiveelements 410 may provide a different resistive value to the path 414between the points 416 and 420. The circuit 408 may also include a firstanalog to digital converter 412 coupled on a path 414 of the audiosignal from the audio source 404 to the output device 406 at a point416. The circuit also includes a second analog-to-digital converter 418coupled to the path 314 at a point 420. Both the first analog-to-digitalconverter 412 and the second analog-to-digital converter 418 may befurther coupled to one or more processors 422 for determining a soundpressure level of the sound generated by the output device 406.

Once the current is measured or calculated, the processors 422 maycalculate the sound pressure level by multiplying the voltage sampled atthe point 420 by the current calculated above and a value indicative ofthe efficiency of the output device 406. In some cases, the processor422 calculate the sound pressure level using a predetermined or staticefficiency value. In some cases, the processor 422 may determine thatthe sound pressure level is too high or may be causing damage as theduration of listing at the current sound pressure level has overexposedthe user. In these cases, the processor 422 may alert the user bycausing a switch 424 or other control mechanism to change the resistivevalue by switching restive element within the path 414 between points416 and 420. For example, the processor 422 may cause the switch 424 toswitch the restive value 410(1)-(N) a predetermined number of timeswithin a given period of time to alter the user by causing the outputdevice 406 to output a clicking noise or other predetermined sound inresponse to the change in resistance.

In some implementations, the processor 422 may cause the switch 424 toincrease the resistive value of the path 414 between the points 416 and420 in response to determining that the sound pressure level isindicative of potential permanent hearing damage. By increasing theresistance on the path 414 between the audio source 404 and the outputdevice 406, the sound pressure level may be reduced at the output device406 without a corresponding reduction in volume at the audio source 404.Thus, the sound quality device 402 may both monitor the sound pressurelevel at the output device 406 and maintain the sound pressure level ata safe level even during extended periods of listening.

In some examples, the processor 422 may cause the switch 424 to apply aresistive element 410 to the path 414 based in part on the measuredvoltage, the calculated current, and/or the sound pressure level. Forexample, the resistive element 410 may be selected to reduce the soundpressure level to reduce the potential hearing damage to a user.

In one particular implementation, the switch 424 or other controlmechanism within the sound quality device 402 may switch to a highresistive element 410 upon activation of the sound quality device 402,activation of the audio source 404, or upon initially receiving an audiosignal from the audio source 404. In this manner, the sound qualitydevice 402 may prevent the output of sound having an excessive soundpressure level as a result of an individual turning the audio source 404off with the volume at a high or above normal level. In some instances,the processor 422 may cause the switch to a resistive element 410 havinga lower resistive value over time (e.g., after 3 seconds or 5 seconds)to gradually adjust the sound to the level indicated by the user at theaudio source 404. In some particular instances, the processor 422 maycause the switch 424 to adjust the resistive element 410 multiple timesbefore returning to the restive element 410 having the lowest resistivevalue.

FIG. 5 illustrates a partial circuit diagram 500 showing selectcomponents of a sound quality device 502 according to someimplementations. In the illustrated example, the sound quality device502 is coupled between an audio source 504 and an output device 506. Forexample, the sound quality device 502 may be configured to couple inlinebetween an audio source 504 or other audio producing device and anoutput device 506 or speaker. In some cases, the interface may be a TRSconnector or other audio input that produces the left audio and rightaudio as separate signals, for instance to produce surround sound.

The sound quality device 502 may include an audio path 508. The path 508may include a first inductor 510 with a first electrode coupled to afirst electrode of a second inductor 512 and a first electrode of afirst resistor 516. The second inductor 512 may have a second electrodecoupled to a first electrode of a third inductor 514 and a firstelectrode of a first switch 518. The third inductor 514 may have asecond electrode coupled to a first electrode of a second resistor 520.

The first resistor 516 may have a second electrode coupled to a firstelectrode of a first capacitor 522. The first capacitor 522 may have asecond electrode coupled to ground or a common terminal (not shown) ofthe audio source 504. The first switch 518 may have a second electrodethat is releasably coupled to a first electrode of one of a plurality ofresistive elements, generally indicated by 524(1)-(K). Each of theplurality of resistive elements 524 may have a second electrode coupledto a first electrode of a second capacitor 526 and a first electrode ofa second switch 528. The second capacitor 526 may have a secondelectrode coupled to ground or the common terminal (not shown) of theaudio source 504. The second switch 528 may have a second electrode thatis releasably coupled to a first electrode of one of a plurality ofaudio modification components, generally indicated by 530(1)-(N).

In some implementations, a controller 538 may be configured to provide acontrol signal to the switch 518 to cause the switch 518 to select arestive element 524(1)-(K). Likewise, the controller 538 may also beconfigured to provide a control signal to the switch 528 to cause theswitch 528 to couple to a particular one of the audio modificationcomponents 530(1)-(N). In other implementations, the processor 536 maybe configured to provide the control signals to either of the switches518 or 528.

In the illustrated example, the inductors 512-514 and capacitors 522 and526 may act to impede the distortion introduced by the output device 506and environmental noise captured by the output device 506 from feedingback into the audio source 504. The inductors 512-514 and capacitors 522and 526 may also act to filter the ultrasonic frequencies from the audiosignal generated by the audio source 504.

Additionally, the plurality of resistive elements 524(1)-(K) may beutilized to further improve the frequency response, while maintain apredetermined level of distortion rejection, noise rejection and/ormicrophonic rejection. In some cases, the switch 518 may be configuredto couple to one of the resistive elements 524(1)-(K) to provide anfrequency response based at least in part on one or more characteristics(e.g., efficiency) of the output device.

For instance, in some situations, harmonic distortion may be generatedby the mechanical or the magnetic components of the output device 506 asthe audio signal is output as sound. For example, the magneticcomponents may generate frequencies or overtones that are not part ofthe original audio signal based on a position of the mechanical (ormoving) components of the output device 506 in relation to the magneticcomponents. In some instances, the harmonic distortion may be output bythe speakers of the output device 506. In other cases, the output device506 may generate intermodulation distortion as the magnetic componentsinteract with the mechanical components. The intermodulation distortionmay present itself as a mixing of the original audio signal, whichgenerates additional frequencies or sounds that are detectable by thehuman ear.

Additionally, in some situations, environmental noise may also becoupled with the audio signal as the output device 506 may act, at leastin part, as a microphone. For example, the in-ear monitors worn bymusicians when on stage to attenuate the volume of the music and protectthe musician's ears often acts as microphone that detects and transfersenvironmental sound (e.g., stage and audience noise) back into theamplifiers, which may then be coupled into the audio signal.

In general, one or more of the harmonic distortion, the intermodulationdistortion, and/or the environmental noise may be coupled back to theaudio source 504 as feedback. In some cases, the audio source 504 mayincorporate the feedback into the audio signal as the audio signal ispassed to the output device 504. The output device 504 in turn generatessound based on the audio signal including the frequencies associatedwith the feedback, thereby reducing the quality of the sound generatedor causing the output of frequencies that are not part of the originalaudio signal.

In other situations, the audio source 504 itself may reduce the qualityof the sound generated by the speaker. For example, some types ofamplifiers, such as electronic amplifier, generate ultrasonic noise.While ultrasonic noise may not be directly detectable by the human ear,the ultrasonic noise may cause the driver of a speaker of the outputdevice 506 to vibrate at the ultrasonic frequencies and couple with themagnetic components of the speaker to introduce irregularities in thesound output by the speaker within the frequencies detectable by thehuman ear. In some cases, the ultrasonic noise within the audio signalalso increases the rate at which the speaker generates harmonic andintermodulation distortion and thereby degrades the sound quality asdiscussed above.

While, the inductors 510-514 and capacitors 522 and 526 may act toimpede the distortion introduced by the output device and environmentalnoise captured by the output device from feeding back into theamplifier, the plurality of resistors 524(1)-(K) may further aid in theattenuation of the distortion and noise feeding back from the outputdevice. In some cases, the resistors 524(1)-(K) act to flatten the audiosignal as the audio signal may be passed to the output device and,thereby to maintain the high end frequencies of the audio signal, whilestill cutting off the ultrasonic noise.

In some specific examples, the resistive value coupled to the path 508by the switch 518 may be selected based on characteristic of the outputdevice 506. For example, as discussed above, the user may inputidentification information (e.g., a make and model) associated with theoutput device 506 via an application operating on a device, such as theaudio source 504. The application may cause the device to provide theidentification information to the sound quality device via acommunication interface. The sound quality device 504 may then selectone of the resistive element 524(1)-(K) to provide an further improvedfrequency response and distortion rejection.

The plurality of audio modification components 530(1)-(N) may beintroduced into the audio path 508 to modify the audio signal prior toaudio being output by the output device 506. For example, the audiomodification component 530(1) may reduce high range frequencies, whilethe audio modification component 530(2) may reduce low rangefrequencies. In some cases, the sound quality device may receive anindication of the hearing capabilities of a user listening to the soundoutput by the output device 506 and select the audio modificationcomponent 530(1)-(K) to apply to the audio signal based at least in parton the hearing capabilities.

The resistor 520 may be a resistor having a known resistive value. Therestive value may be the resistive value of the routing wire betweenpoints 532 and point 534. In some cases, a first analog to digitalconverter (not shown) may be coupled to point 532 and a secondanalog-to-digital converter (not shown) may be coupled to the point 534.Both the first analog-to-digital converter and the secondanalog-to-digital converter may be further coupled to a processor 536.The processor 536 may calculate or determine a sound pressure level ofthe sound generated by the output device 506 based at least in part on aseries of voltages sampled at the first point 532 and a series ofvoltages sampled at the second point 534, as described above withrespect to FIGS. 1-4.

FIG. 6 illustrates a partial circuit diagram 600 showing a selectcomponents 602, 610, and 616 which may be utilized as one or more of theaudio modification component 530(1)-(K) of FIG. 5. As described abovewith respect to FIG. 5, the sound quality device may receive anaudiogram, hearing profile, or component selection from an audio source.The sound quality device may then select a component, such as components602, 610, or 616, to modify the audio signal to provide an improvedlistening experience for the user that is tailored to the user's hearingloss or capabilities.

In the illustrated example, the component 602 includes an inductor 604coupled to a first end of a resistive element 606. The resistive element606 has a second end that coupled to a capacitor 608. In general, thecomponent 602 has the effect of attenuating the middle frequency of theaudio signal, while passing the high and low end frequency. Thus, thecomponent 602 provide the equivalent of increasing the volume of thehigh and low end frequencies with respect to the mid-range frequencies.

In the illustrated example, the component 610 includes an inductor 612coupled to a first end of a resistive element 614. In general, thecomponent 610 has the effect of boasting the high end frequencies of theaudio signal, while passing the mid-range and low-end frequency. Thus,the component 610 provide the equivalent of increasing the volume of thehigh with respect to the mid-range and low-range frequencies.

In the illustrated example, the component 616 includes an capacitor 618coupled to a first end of a resistive element 620. In general, thecomponent 616 has the effect of boasting the low end frequencies of theaudio signal, while passing the high and mid-range frequency. Thus, thecomponent 610 provide the equivalent of increasing the volume of thelow-range frequencies with respect to the mid-range and high-endfrequencies.

FIG. 6 provides one example of a component 602 that may be incorporatedinto the circuit of FIG. 5 to modulate the audio signal to accommodatethe user's hearing loss. Thus, it should be understood, that many othercomponents may be incorporated into the circuit of FIG. 5 in addition toor in lieu of the component 602.

FIGS. 7-11 are flow diagrams illustrating example processes associatedwith the circuits of FIGS. 1-5. The processes are illustrated as acollection of blocks in a logical flow diagram, which represent asequence of operations, some or all of which can be implemented inhardware, software or a combination thereof. In the context of software,the blocks represent computer-executable instructions stored on one ormore computer-readable media that, which when executed by one or moreprocessors, perform the recited operations. Generally,computer-executable instructions include routines, programs, objects,components, data structures and the like that perform particularfunctions or implement particular abstract data types.

The order in which the operations are described should not be construedas a limitation. Any number of the described blocks can be combined inany order and/or in parallel to implement the process, or alternativeprocesses, and not all of the blocks need be executed. For discussionpurposes, the processes herein are described with reference to theframeworks, architectures and environments described in the examplesherein, although the processes may be implemented in a wide variety ofother frameworks, architectures or environments.

FIG. 7 is an example flow diagram showing an illustrative process 700according to some implementations. For instance, a sound quality devicemay be coupled between an audio source and an output device to monitorthe sound pressure level of the sound output by the output device inreal time. In some cases, the sound quality device may notify the userif the sound pressure level presents a danger to the user's hearing. Insome particular implementations, the sound quality device may alsoreduce or lower the sound pressure level without assistance from theaudio source.

As described above, the sound pressure level is a result of the currentof the audio signal, the voltage of the audio signal, and the efficiencyof the speaker that outputs the audio. However, in many cases, the audiosource is associated with a different device or product than the speaker(e.g., a smart phone or audio player versus a headset or earbud system).In these cases, the audio source may be aware of the voltage level butnot the current or efficiency, while the ear bud or speaker may be awareof the efficiency but not the voltage or current. Thus, in these cases,the sound quality device may be coupled between the audio source and theoutput device to more accurately monitor the sound pressure levelassociated with the sound output to the user.

At 702, the sound quality device receives an audio signal from the audiosource. For example, the sound quality device may be coupled to theaudio source via a TRS or USB connection interface. In some cases, theaudio signal may include a mono signal or a stereo signal.

At 704, the sound quality device measures the voltages associated withthe audio signal. For example, the sound quality device may measure thevoltage on each terminal of a resistor of known resistive value throughwhich the audio signal passes. In some cases, the voltage measured atone terminal of the known resistive value may be the voltage used tocalculate the sound pressure level of the sound generated by the outputdevice.

At 706, the sound quality device may calculate the current associatedwith the audio signal. For example, the sound quality device may includea processor that may calculate the current using the two sampled ormeasured voltages and the known resistive value.

At 708, the sound quality device may calculate the sound pressure levelusing the voltage measured after the known resistive value and thecurrent. In some cases, the sound quality device may also use anefficiency value of the speaker to more accurately calculate the soundpressure level. In one example, the efficiency may be a static orpredetermined value that the sound quality device uses regardless of theoutput device coupled to the sound quality device.

At 710, the sound quality device determines that damage may be beingcaused to the user's hearing based at least in part on the soundpressure level. For example, the sound quality device may determine thatdamage may occur if the sound pressure level is greater than a thresholdvalue. In other cases, the sound quality device may monitor or recordthe sound pressure level over time and determine that damage may occurwhen the sound pressure level is above one or more threshold for apredetermined period of time. For example, the sound quality device maymonitor the sound pressure level over time based on the OSHA guidelines.

At 712, the sound quality device may alert the user to the potential forhearing damage. For example, the sound quality device may add apredetermined noise or sound to the audio signal prior to providing orsending the audio signal to the output device. Thus, the user may bealtered via the noise or sound being generated along with the audiosignal by the output device.

At 714, the sound quality device may adjust a resistive value associatedwith the audio path to reduce the sound pressure level. For example, inlieu of or in addition to alerting the user as to the potential forhearing damage the sound quality device may insert a higher resistivevalue into the audio path of the audio signal to thereby reduce thesound pressure level of the sound generated by the output device.

FIG. 8 is an example flow diagram showing an illustrative process 800according to some implementations. For instance, a sound quality devicemay be coupled between an audio source and an output device to monitorthe sound pressure level of the sound output by the output device inreal time. In some cases, the sound quality device may notify the userif the sound pressure level presents a danger to the user's hearing. Insome particular implementations, the sound quality device may alsoreduce or lower the sound pressure level without assistance from theaudio source.

As described above, the sound pressure level is a result of the currentof the audio signal, the voltage of the audio signal, and the efficiencyof the speaker that outputs the audio. However, in many cases, the audiosource is associated with a different device or product than the speaker(e.g., a smart phone or audio player versus a headset or earbud system).In these cases, the audio source may be aware of the voltage level butnot the current or efficiency, while the ear bud or speaker may be awareof the efficiency but not the voltage or current. Thus, in these cases,the sound quality device may be coupled between the audio source and theoutput device to more accurately monitor the sound pressure levelassociated with the sound output to the user.

At 802, the sound quality device receives an audio signal from the audiosource. For example, the sound quality device may be coupled to theaudio source via a TRS or USB connection interface. In some cases, theaudio signal may include a mono signal or a stereo signal.

At 804, the sound quality device measures the voltages associated withthe audio signal. For example, the sound quality device may measure thevoltage on each terminal of a resistor of known resistive value throughwhich the audio signal passes. In some cases, the voltage measured atone terminal of the known resistive value may be the voltage used tocalculate the sound pressure level of the sound generated by the outputdevice.

At 806, the sound quality device may calculate the current associatedwith the audio signal. For example, the sound quality device may includea processor that may calculate the current using the two sampled ormeasured voltages and the known resistive value.

At 808, the sound quality device receives the efficiency value from theaudio source. For example, the sound quality device may be in wirelesscommunication with the audio source and a sound quality application maybe installed on a computer readable media of the audio source. Using thesound quality application, the user may select the make and model of theoutput device coupled to the sound quality device. The sound qualityapplication may also include a data related to the efficiency of variousor commonly used output devices. In some specific examples, the soundquality device may be in communication with another device other thanthe audio source that may provide the efficiency. For example, the usermay utilize a smart phone or other computing device to enter theefficiency, while the audio source may be stereo system.

At 810, the sound quality device may calculate the sound pressure levelusing the voltage measured after the known resistive value, the current,and the efficiency received from the audio source.

At 812, the sound quality device determines that damage may be beingcaused to the user's hearing based at least in part on the soundpressure level. For example, the sound quality device may determine thatdamage may occur if the sound pressure level is greater than a thresholdvalue. In other cases, the sound quality device may monitor or recordthe sound pressure level over time and determine that damage may occurwhen the sound pressure level is above one or more threshold for apredetermined period of time. For example, the sound quality device maymonitor the sound pressure level over time based on the OSHA guidelines.

At 814, the sound quality device may alert the user to the potential forhearing damage. For example, the sound quality device may cause theaudio source or other device in wireless communication to generate avisual, audible or tactile notification that may alter the user to thepotential for hearing damage.

In some alternative implementations, the sound quality device mayprovide the voltage and current to a device, such as the audio source,in communication with the sound quality device. The other device maythen calculate the sound pressure level on behalf other sound qualitydevice and alert the user via an audible, tactile, or visualnotification at the device.

At 816, the sound quality device may adjust a resistive value associatedwith the audio path to reduce the sound pressure level. For example, inlieu of or in addition to alerting the user as to the potential forhearing damage the sound quality device may insert a higher resistivevalue into the audio path of the audio signal to thereby reduce thesound pressure level of the sound generated by the output device.

FIG. 10 is an example flow diagram showing an illustrative process 1000according to some implementations. For example, the sound quality devicemay act as a scream protection device. When switching audio signals or,for instance tracks or albums at the audio source, the volume levelassociated with the audio signal may differ. In these cases, the soundquality device may switch to a high resistive path for a predeterminedamount of time upon the activation of the device, receiving a new ordifferent audio signal, or at any time the sound pressure level exceedsa threshold.

At 1002, the sound quality devise receives an enablement signal form theaudio source. In some cases, the enablement signal may be a signalindicating the audio source has been activated. In other cases, theenablement signal may be an indication that a new track or new audiosignal has been selected for output by the output device. In still othercases, the enablement signal may be the audio signal itself.

At 1004, the sound quality device selects a first path for the audiosignal. The first path may have a high resistive value in order toreduce the sound pressure level to a safe level. In some cases, thesound quality device may select the first path in response to receivingthe enablement signal.

At 1006, the sound quality device receives an audio signal from theaudio source. For example, the sound quality device may continue toreceive the audio signal or being to receive the audio signal followingthe enablement signal.

At 1008, the sound quality device selects a second path for the audiosignal. The second path may have a resistive value lower than the firstpath. In this manner, the sound quality device may bring the soundgenerated by the output device closer to the level intended by thesettings of the audio source.

At 1010, the sound quality device selects a third path for the audiosignal. The third path may have a resistive value lower than the secondpath. In this manner, the sound quality device may again bring the soundgenerated by the output device closer to the level intended by thesettings of the audio source. In the current example, the sound qualitydevice may return to the lowest resistive path after three switches butin other examples any number of resistive levels may be switched betweento bring the sound generated by the output device gradually closer andcloser to the audio signal generated by the audio source.

FIG. 11 is an example flow diagram showing an illustrative process 1100according to some implementations. In some cases, the sound qualitydevice may be configured to accommodate for the user's particularhearing profile. For example, the sound quality device may include oneor more paths that may provide various customized audio settings, asdescribed above with respect to FIGS. 5 and 6. In some implementations,the sound quality device or a sound quality application associated withthe sound quality device operating on another device, such as the audiosource may cause the user's hearing to be tested.

At 1102, the audio source may generate a hearing assessment. Forexample, the audio source may generate a number of tones, parts ofspeech, or sentences with known characteristics. In response to eachtone, part of speech, or sentences generated the audio source mayreceive a user input. Based at least in part on the user inputs and theknown characteristics, the sound quality application on the audio sourcemay determine the hearing result of the user.

At 1102, the sound quality application operating on the audio source maydetermine the user's hearing capabilities based at least in part on theresults of the audio assessment. For example, the sound qualityapplication may determine the user has low-end, mid-range, or high-endhearing loss. In other cases, the sound quality application may measurethe extent of loss over various frequency bands.

At 1104, the sound quality application may select an audio modificationbased at least in part on the user's hearing capabilities. For example,the sound quality device may include multiple paths that may alter ormodify the audio signal in some manner (for instance, the path describedabove with respect to FIG. 6 lowers the low and high end frequency bandsof the audio signal).

At 1106, the sound quality application may cause the host device tonotify the sound quality device as to the selected modification. Forexample, the host device and the sound quality device may be incommunication via a short range wireless communication protocol or anear field wireless network.

At 1108, the host device may provide an audio signal to an output devicevia the sound quality device. For instance, when the host device is theaudio device of FIGS. 1-5, the host device may provide both the selectedmodification and the audio signal.

FIG. 12 illustrates an example architecture of an audio device 1200 ofFIGS. 1-5 according to some implementations. In some implementations,the audio device may host or include a sound quality applicationassociated with a sound quality device. For example, the audio devicemay be a cellular telephone, smart phone, portable media player, tabletcomputer, wearable computer, laptop computer, netbook, desktop computer,television, appliance, home electronic device, automotive electronicdevice, augmented reality device, and so forth.

The device 1200, generally, includes one or more user interfaces 1202for presenting information or data and for receiving user inputs. Theuser interfaces 1202 may include one or more output components, such asa display or touch screen, and one or more input components, such askeyboards, keypads, joysticks, a mouse, a touch screen, touch pad,drawing pad, or control buttons. In some implementations, the outputcomponents and input components are combined in a single user interface1202 to provide a touch-sensitive display, or touch screen display. Forinstance, in the illustrated example, the user interface 1202 includesone or more displays 1204 for presenting information, such as datarelated to a hearing assessment or selectable options associated with anaudio track, to a user, one or more sensors 1206 for accepting inputresulting from contact and/or application of incident force, such as auser finger or stylus pressing upon one of the sensor 1206. In somespecific implementations, the device 1200 may be configured to receiveuser inputs by communicating with an active stylus or other remotecontrol device. For example, the active stylus and the device 1200 mayactively exchange data related to the user inputs.

In some cases, the sensors 1206 may be a touch sensor couple to a touchlayer (not shown), such as an indium tin oxide (ITO) layer arranged in agrid pattern below the top surface of the display 1204. In this case,the touch sensor is configured to determine characteristics of userinteraction with the display 1204 detected by the ITO layer. Thesecharacteristics may include the location of the touch on the display1204, magnitude of the force, shape of the touch, and so forth.

In some implementations, the display 1204 may present content in ahuman-readable format to a user. The display 1204 may be reflective,emissive, or a combination of both. Reflective displays utilize incidentlight and include electrophoretic displays, interferometric modulatordisplays, cholesteric displays, and so forth. Emissive displays do notrely on incident light and, instead, emit light. Emissive displaysinclude backlit liquid crystal displays (LCDs), time multiplexed opticalshutter displays, light emitting diode (LED) displays, and so forth.When multiple displays are present, these displays may be of the same ordifferent types. For example, one display may be an electrophoreticdisplay while another may be a liquid crystal display. In someimplementations, multiple displays 1204 may be present and/or coupled tothe device 1200. These multiple displays 1204 may be located in the sameor different enclosures or panels.

The device 1200 also includes one or more communication interfaces 1208to facilitate communication between one or more networks (such as theInternet® or one or more local area networks), directly with one or moredevices (such as a sound quality device), and/or with one or more cloudservices (such as an audio streaming service). The communicationinterfaces 1208 may also facilitate communication between one or morewireless access points, a master device, and/or one or more othercomputing devices as part of an ad-hoc or home network system. Thecommunication interfaces 1208 may support both wired and wirelessconnection to various networks, such as cellular networks, radio, WiFinetworks, short-range or near-field networks (e.g., Bluetooth®),infrared signals, local area networks, wide area networks, the Internet,and so forth.

The device 1200 includes or accesses components such as at least one ormore control logic circuits, central processing units, or processors1210, and one or more computer-readable media 1212 to perform thefunction of the device 1200. Additionally, each of the processors 1210may itself comprise one or more processors or processing cores.

Depending on the configuration of the device 1200, the computer-readablemedia 1212 may be an example of tangible non-transitory computer storagemedia and may include volatile and nonvolatile memory and/or removableand non-removable media implemented in any type of technology forstorage of information such as computer-readable instructions ormodules, data structures, program modules or other data. Suchcomputer-readable media may include, but is not limited to, RAM, ROM,EEPROM, flash memory or other computer-readable media technology,CD-ROM, digital versatile disks (DVD) or other optical storage, magneticcassettes, magnetic tape, solid state storage, magnetic disk storage,RAID storage systems, storage arrays, network attached storage, storagearea networks, cloud storage, or any other medium that can be used tostore information and which can be accessed by the processors 1210.

Various instruction, information, data stores, and so forth may bestored within the computer-readable media 1212 and configured to executeon the processors 1210. For instance, the computer-readable media 1212may store one or more applications, such as a sound quality application1214). In some cases, the sound quality application 1214 may includeinstructions which when executed by the processors 1210 cause the device1200 to improve the user's listening experience. For example, in theillustrated example, the sound quality application 1214 may include ahearing assessment module 1216, a sound pressure level module 1218,and/or an audio modification selection module 1220.

The computer-readable media 1212 may also store various data associatedwith the sound quality application 1214. For example, thecomputer-readable media 1212 may store audio content 1222 to provide tothe output device, hearing capabilities records 1224, and/or variousefficiencies associated with different output devices.

In some cases, the hearing assessment module 1216 may be configured togenerate various tones, signals, parts of speech, etc. at the device1200 and to send the various tones, signals, parts of speech, etc. to anoutput device for output as sound. The hearing assessment module 1216may also be configured to receive user inputs, for instance, via theuser interface 1202 in response to the output of the tones, signals,parts of speech, etc. In this manner, the hearing assessment module 1216may determine the user's hearing capabilities 1224.

The sound pressure level module 1218 may be configured to receive datasuch as various sampled voltages and measured currents from a soundquality device via the communication interfaces 1208. The sound pressurelevel module 1218 may then be able to calculate the sound pressure levelof the sound generated by the output device using the received voltagesand current as well as the stored efficiencies 1226. The sound pressurelevel module 1218 may also measures the user's exposure to the soundpressure level over time. In some cases, the sound pressure level module1218 may alter the user via the user interfaces 1208 if the user isexposed to potential hearing damage. In other cases, the sound pressurelevel module 1218 may cause the sound quality device to alter aresistive value associated with the audio path of the audio signal inorder to reduce the sound pressure level when there is potential forhearing damage.

In another example, the sound pressure level module 1218 may receive arequest from the sound quality device via the communication interfaces1208. The sound pressure level module 1218 may request the user selectan identifier associated with the output device (e.g., a make andmodel). The sound quality device may then determine the efficiency 1226of one or more speakers of the output device based at least in part onthe identifier selected by the user. The sound pressure level module1218 may cause the communication interface 1208 to send the efficiency1226 to the sound quality device for further processing.

The audio modification selection module 1220 may be configured determineif a modification to the audio signal by the sound quality device mayimprove the listening experience of the user. For example, the audiomodification selection module 1220 may select the audio modificationbased at least in part on the user's hearing capability records 1224.The audio modification selection module 1220 may also send the audiomodification to the sound quality device via the communication interface1208.

FIG. 13 illustrates an example architecture of a sound quality device1300 of FIGS. 1-5 according to some implementations. The sound qualitydevice 1300 may be coupled between an audio source and an output deviceto monitor the sound pressure level of the sound generated by the outputdevice in real time. The sound quality device may also be configured tonotify the user if the sound pressure level presents a danger to theuser's hearing. In some particular implementations, the sound qualitydevice may also reduce or lower the sound pressure level withoutaffecting the volume associated with the audio signal.

The sound quality device 1300 includes one or more communicationinterfaces 1302 to facilitate communication between one or more networks(such as the Internet® or one or more local area networks), directlywith one or more devices (such as the audio source or the device 1200 ofFIG. 12), and/or with one or more cloud services (such as the foreignlanguage acquisition system). The communication interfaces 1302 may alsofacilitate communication between one or more wireless access points, amaster device, and/or one or more other computing devices as part of anad-hoc or home network system. The communication interfaces 1302 maysupport both wired and wireless connection to various networks, such ascellular networks, radio, WiFi networks, short-range or near-fieldnetworks (e.g., Bluetooth®), infrared signals, local area networks, widearea networks, the Internet, and so forth.

The sound quality device 1300 includes or accesses components such as atleast one or more control logic circuits, central processing units, orprocessors 1304, and one or more computer-readable media 1306 to performthe function of the device 1300. Additionally, each of the processors1304 may itself comprise one or more processors or processing cores.

Depending on the configuration of the device 1300, the computer-readablemedia 1306 may be an example of tangible non-transitory computer storagemedia and may include volatile and nonvolatile memory and/or removableand non-removable media implemented in any type of technology forstorage of information such as computer-readable instructions ormodules, data structures, program modules or other data. Suchcomputer-readable media may include, but is not limited to, RAM, ROM,EEPROM, flash memory or other computer-readable media technology,CD-ROM, digital versatile disks (DVD) or other optical storage, magneticcassettes, magnetic tape, solid state storage, magnetic disk storage,RAID storage systems, storage arrays, network attached storage, storagearea networks, cloud storage, or any other medium that can be used tostore information and which can be accessed by the processors 1304.

Various instruction, information, data stores, and so forth may bestored within the computer-readable media 1306 and configured to executeon the processors 1304. For instance, the computer-readable media 1306may store a resistive selection module 1308, an audio modification pathselection module 1310, or a sound pressure level module 1312. Thecomputer-readable media 1306 may also store a table of efficiencies 1314that may be used to determine the sound pressure level.

The resistive selection module 1308 may be configured to switch betweenresistive paths to reduce the sound pressure level of the soundgenerated by the output device. The audio modification path selectionmodule 1310 may be configured select an audio modification toaccommodate for the hearing capabilities of the user, as described abovewith respect to FIG. 5.

The sound pressure level module 1312 may be configured to sample thevoltage of the audio signal at various points. Using the sampledvoltages, the sound pressure level module 1312 may calculate the currentof the audio signal. The sound pressure level module 1312 may alsomeasure an impedance of the audio signal and infer or look up anefficiency 1320 in the computer-readable media 1306.

Although the subject matter has been described in language specific tostructural features, it is to be understood that the subject matterdefined in the appended claims is not necessarily limited to thespecific features described. Rather, the specific features are disclosedas illustrative forms of implementing the claims.

What is claimed is:
 1. A device comprising: an input interface toreceive an audio signal from an audio source; an output interface togenerate sound from the audio signal; a first audio path having a firstresistive element; a second audio path having a second resistiveelement, the second resistive element having a resistive value less thanthe resistive value of the first resistive element; and a circuitcoupled to the input interface and the output interface, the circuit to:couple the first audio path to the input interface in response todetecting the audio signal; decouple the first audio path and to couplethe second audio path to the input interface in response to a firstperiod of time elapsing; monitor a current associated with the audiosignal for a second period of time substantially temporally with thefirst period of time; determine a potential for hearing damage based atleast in part on the monitoring; and causing the output interface tosend an alert associated with the potential for hearing damage.
 2. Thedevice as recited in claim 1, wherein: the input interface is releasablycoupled to the audio source; and the output interface is releasablycoupled to an output device.
 3. The device as recited in claim 1,wherein the circuit includes: a switch to couple and de-couple the firstaudio path and the second audio path.
 4. The device as recited in claim1, wherein the circuit is configured to couple the first audio path inresponse to receiving the audio signal.
 5. The device as recited inclaim 4, wherein the circuit is configured to decouple the first audiopath and couple the second audio path in response to the period of timeexceeding a time threshold.
 6. The device as recited in claim 5, whereinthe time threshold is a period less than fifteen seconds.
 7. The deviceas recited in claim 1, further comprising: a third audio path, the thirdaudio path having a resistive value less than the resistive value of thesecond audio path; and wherein the circuit is configured to: couple thefirst audio path in response to receiving the audio signal; decouple thefirst audio path and couple the second audio path in response to theperiod of time exceeding a first time threshold; and decouple the secondaudio path and couple the third audio path in response to the period oftime exceeding a second time threshold, the second time thresholdgreater than the first time threshold.
 8. The device as recited in claim1, further comprises: at least one inductor coupled between the firstinterface and the circuit; and at least one capacitor coupled betweenthe circuit and the second interface.
 9. A method comprising: receivingat a device, an audio signal from an audio source; selecting a firstaudio path in response to receiving the audio signal, the first audiopath having a first resistive value; initiating a period of time;determining the period of time has exceeded a threshold; selecting asecond audio path in response to the period of time exceeding thethreshold, the second audio path having a second resistive value lessthan the first resistive value initiating a second period of timesubstantially temporally with the first period of time; monitoring adecibel level associated with the audio signal; determining a potentialfor hearing damage to a user based at least in part on the monitoring;and sending an alert to a device associated with the user to alert theuser to the potential for hearing damage.
 10. The method as recited inclaim 9, further comprising: initiating a third period of time;determining the third period of time has exceeded a second threshold;selecting a third audio path in response to the third period of timeexceeding the second threshold, the third audio path having a thirdresistive value less than the second resistive value.
 11. The method asrecited in claim 10, wherein the second threshold is less than the firstthreshold.
 12. The method as recited in claim 9, further comprising:receiving at a device, a second audio signal from the audio source;selecting the first audio path in response to receiving the second audiosignal; initiating the period of time; determining the period of timehas exceed the threshold; selecting the second audio path in response tothe period of time exceeding the threshold.
 13. The method as recited inclaim 9, further comprising: initiating a third period of timesubstantially temporally with the first period of time; determining adecibel level associated with the audio signal; determining a thirdthreshold based at least in part on the decibel level; determining thethird period of time has exceed a third threshold; re-selecting thefirst audio path in response to the third period of time exceeded thethird threshold.
 14. A circuit comprising: a first interface forreleasably coupling to an audio source, the first interface configuredto receive an audio signal from the audio source; a second interface forreleasably coupling to a speaker, the second interface configured tosend the audio signal to the speaker; a first inductor having a firstelectrode coupled to the first interface and a second electrode coupledto a first electrode of a second inductor and a first electrode of afirst resistor; the second inductor having a second electrode coupled toa first electrode of a switch; the first resistor having a secondelectrode coupled to a first electrode of a first capacitor; the switchhaving a second electrode to releasably couple to a first electrode ofone of a plurality restive elements, individual ones of the resistiveelements having different restive values; and the first capacitor havinga second electrode coupled to ground.
 15. The circuit as recited inclaim 14, further comprising: a third inductor having a first electrodecoupled to the second electrode of the second inductor and a secondelectrode coupled to the output interface.
 16. The circuit as recited inclaim 14, further comprising: individual ones of the plurality ofresistive elements having a second electrode coupled to a secondcapacitor; and the second capacitor having a second electrode coupled tothe ground.
 17. The circuit as recited in claim 14, further comprising:individual ones of the plurality of resistive elements having a secondelectrode coupled to a first electrode of an audio modificationcomponent; and the audio modification component having a secondelectrode coupled to the ground.
 18. The circuit as recited in claim 14,further comprising: a third inductor having a first electrode coupled tothe second electrode of the second inductor and a second electrodecoupled to a first electrode of a second resistor and a first node; thesecond resistor having a second electrode coupled to a second node;wherein a first set of voltages may be sampled at the first node and asecond set of voltages may be sampled at the second node.
 19. Thecircuit as recited in claim 18, further comprising: one or moreprocessors coupled to the first node and to the second node, the one ormore processors to calculate a current based at least in part on thefirst set of voltages and the second set of voltages and a soundpressure level based at least in part on the second set of voltages andthe current.